A cross-linked or at least partially cross-linked thermoplastic elastomeric composition formed of from 10 to 90 percent of a first polymeric material comprised of ethylene, &agr;-olefin and optionally a non-conjugated diene, and 90 to 10 percent of a second olefin polymeric material, wherein at least one of the first or second polymeric materials is at least partially the product of a metallocene polymerization reaction.